Optical instrument, and method for manufacturing optical instrument

Abstract

To provide a lens barrel part that is formed of carbon fiber reinforced resin, is excellent in strength including impact resistance performance, is reduced in size or weight and thickness, and has high-quality appearance.SOLUTION: Carbon fiber braid layers 3 and 5 assembled in a cylindrical shape and endlessly in a circumferential direction of the cylindrical shape, and a one-directional prepreg sheet layer 4 formed of carbon fiber oriented in one direction, are solidified and coupled to each other with thermoplastic resin to form a cylindrical body 1. The braid layer 3 and 5 are braided in an endless cylindrical shape on a mandrel in a circumferential direction of the mandrel, with the one-directional prepreg sheet layer 4 located therebetween.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a lens barrel component made of carbon fiber reinforced resin, an optical device, and a method for manufacturing the lens barrel component. [Background technology]

[0002] Conventionally, interchangeable camera lenses, such as telephoto lenses with focal lengths of over 300 mm, have been large and weigh on the order of several kilograms. Even for optical devices with such a focal length range, there is a demand for products that are lightweight and strong, from the standpoint of portability and improved operability during shooting.

[0003] Conventionally, the lens barrels of these large optical devices have been made of aluminum alloys or magnesium alloys because of their impact resistance. The hoods attached to these lenses have also been made of aluminum alloys because of their impact resistance. However, even though these metal materials are light metals, there is a limit to how much they can be made lighter.

[0004] In recent years, therefore, it has been considered to manufacture lens barrels and hoods using carbon fiber reinforced plastic (CFRP), which is carbon fiber impregnated with thermosetting resin such as epoxy. When manufacturing lens barrel parts using carbon fiber reinforced plastic (CFRP), for example, the shape is formed using a manufacturing method called the sheet winding method (SW method), in which a unidirectional prepreg sheet, in which carbon fibers are aligned in one direction, is wound around a cylindrical mold called a mandrel. After that, the carbon fibers are impregnated with thermosetting resin such as epoxy and hardened in an autoclave or the like.

[0005] However, depending on the direction in which the carbon fibers are aligned and the combination of layers, there are cases where the obtained strength differs and the desired impact resistance cannot be obtained. Therefore, in order to solve such problems, first, unidirectional prepreg sheets are laminated in a single layer or multiple layers in the axial direction and circumferential direction of the lens barrel, respectively, and integrated. Then, a configuration has been proposed in which the final unidirectional prepreg sheet in the circumferential direction is wrapped around the outside of the unidirectional prepreg sheet in the axial direction to obtain impact resistance (Patent Document 1 below). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4813619 Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, in the SW method in which a unidirectional prepreg sheet is wrapped around a mandrel, a seam is inevitably generated in the manufacturing process, and there is a possibility that the strength varies at the seam, for example, that the impact resistance performance decreases. Therefore, a countermeasure is considered in which the unidirectional prepreg sheet to be wrapped around the mandrel is laminated in multiple layers, and the position of the seam is shifted at that time. However, it becomes necessary to compensate for the strength deterioration due to the seam by increasing the number of layers, and there is a concern that the effect of weight reduction will be reduced. In addition, the presence of the seam may cause a difference in hardening shrinkage between the seam and other parts during the sintering process in which the impregnated resin is hardened and the shape is formed, and as a result, the roundness of the telescope barrel may not be obtained. In addition, when the impregnated resin is a thermosetting resin such as epoxy that has a long hardening time, there is a concern that productivity will decrease.

[0008] An object of the present invention is to provide a lens barrel component which is made of carbon fiber reinforced resin, has excellent strength such as impact resistance, is small, thin, lightweight, and has a high-quality appearance. [Means for solving the problem]

[0009] A first aspect of the present invention is an optical device configured to be detachable from an imaging device, comprising: a cylindrical body including a first carbon fiber layer which is a cylindrically braided layer, and a cylindrical second carbon fiber layer located on the outer circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer and the second carbon fiber layer being bonded together by a thermoplastic resin which is an integrated combination of a first thermoplastic resin impregnated in the first carbon fiber layer and a second thermoplastic resin impregnated in the second carbon fiber layer; and an optical element, wherein the first carbon fiber layer is arranged so that the carbon fibers of the first carbon fiber layer are braided in a twill weave pattern inclined with respect to the axial direction of the cylindrical body and are endless in the circumferential direction of the cylindrical body, and the second carbon fiber layer is a sheet-shaped carbon fiber layer. A second aspect of the present invention is an optical device configured to be detachable from an imaging device, comprising: a cylindrical body including a first carbon fiber layer which is a cylindrically braided layer, and a cylindrical second carbon fiber layer located on the inner circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer and the second carbon fiber layer being bonded together by a thermoplastic resin which is an integrated combination of a first thermoplastic resin impregnated in the first carbon fiber layer and a second thermoplastic resin impregnated in the second carbon fiber layer; and an optical element, wherein the first carbon fiber layer is arranged so that the carbon fibers of the first carbon fiber layer are braided in a twill weave pattern inclined with respect to the axial direction of the cylindrical body and are endless in the circumferential direction of the cylindrical body, and the second carbon fiber layer is a sheet-shaped carbon fiber layer. A third aspect of the present invention is a method for manufacturing a cylindrical body, comprising the steps of: crossing and braiding a plurality of carbon fibers on a mandrel into a cylindrical shape to form a first carbon fiber layer impregnated with a first thermoplastic resin; forming a second carbon fiber layer on the mandrel impregnated with a second thermoplastic resin; and bonding the first carbon fiber layer and the second carbon fiber layer with the thermoplastic resin by heat treating them, wherein the bonding step is performed under pressure using an outer mold; in the step of forming the first carbon fiber layer, the first carbon fiber layer is provided such that the carbon fibers of the first carbon fiber layer are braided in a twill weave pattern inclined with respect to the axial direction of the cylindrical body and are endless in the circumferential direction of the cylindrical body; and in the step of forming the second carbon fiber layer, the second carbon fiber layer is a sheet-like carbon fiber layer. Effect of the Invention

[0010] According to the above-mentioned configuration, it is possible to provide a lens barrel component that is made of carbon fiber reinforced resin, has excellent strength such as impact resistance, is small, thin, lightweight, and has a high-quality appearance. [Brief description of the drawings]

[0011] [Figure 1] 1A and 1B show the structure of a cylindrical body according to an embodiment of the present invention, in which FIG. 1A is a plan view of the cylindrical body, and FIG. [Diagram 2] FIG. 1 is a perspective view showing a braiding device according to an embodiment of the present invention. [Diagram 3] 1A and 1B show the structure of a cylindrical body according to an embodiment of the present invention, in which FIG. 1A is a plan view of the cylindrical body, and FIG. [Figure 4] 3A and 3B show different structures of a cylindrical body according to an embodiment of the present invention, where (a) is a plan view of the cylindrical body, (b) is a cross-sectional view of the cylindrical body, and (c) is an enlarged cross-sectional view of a portion of the cylindrical body. [Diagram 5] 1A and 1B show yet another different structure of the cylindrical body according to an embodiment of the present invention, where (a) is a plan view of the cylindrical body, (b) is a cross-sectional view of the cylindrical body, and (c) is a cross-sectional view showing an enlarged portion of the cylindrical body. [Figure 6]5(a) to 5(d) are explanatory views showing how insert molding is performed on a cylindrical body according to an embodiment of the present invention. [Figure 7] 1A and 1B show yet another different structure of the cylindrical body according to an embodiment of the present invention, where (a) is a plan view of the cylindrical body, (b) is a cross-sectional view of the cylindrical body, and (c) is a cross-sectional view showing an enlarged portion of the cylindrical body. [Figure 8] 5(a) to 5(d) are explanatory views showing how insert molding is performed on a cylindrical body according to an embodiment of the present invention. [Figure 9] 1A and 1B show an experimental form according to an embodiment of the present invention, in which (a) is a plan view of a sample, (b) is a cross-sectional view of a joint, and (c) is an enlarged cross-sectional view of a part of the joint. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the configurations shown below are merely examples, and those skilled in the art can appropriately change the detailed configurations, for example, without departing from the spirit of the present invention. Also, the numerical values ​​used in the present embodiment are for reference only and do not limit the present invention.

[0013] <Embodiment 1> 1(a) and (b) show a cylindrical continuous carbon fiber reinforced resin molded body (cylindrical body) constituting a lens barrel part in this embodiment in plan view and cross-sectional view. The cylindrical body 1 in FIG. 1(a) and (b) is a cylindrical body forming a lens barrel part in an optical device such as an interchangeable lens of a camera, for example, a lens hood, a focus ring, a body part of a lens barrel, etc., and is configured as a cylindrical continuous carbon fiber reinforced resin molded body. Here, the lens hood is a light-shielding part that blocks unnecessary light other than the shooting light from entering the shooting optical system, and is configured to be detachable from the tip of an optical device (imaging device) such as a camera. In addition, the lens barrel parts such as the outer tube, inner tube, and focus ring of the lens barrel can be considered as lens barrel parts that constitute the body part of the lens barrel that holds or adjusts optical elements such as lenses and mirrors.

[0014] The cylindrical body 1 in FIG. 1 is formed by solidifying a fiber layer (sometimes called a first fiber layer) consisting of carbon fiber braid layers 3 and 5 with a resin. For example, the resin for solidification is preliminarily contained in the fiber layer in the form of impregnation or coating. In other words, an intermediate body 2 is prepared in which a plurality of continuous carbon fibers are preliminarily impregnated with the resin for solidification in the form of impregnation or coating. The intermediate bodies 2 are crossed and assembled into a cylindrical shape to form fiber layers (first fiber layers) such as the braid layer 3 and the braid layer 5. At this time, it is preferable that the plurality of intermediate bodies 2 are assembled at an angle with respect to the axial direction of the cylindrical body. In addition, a second fiber layer (unidirectional prepreg sheet layer) may be formed together with the fiber layer (first fiber layer). In other words, the first fiber layer and the second fiber layer may be solidified with a resin to form the cylindrical body 1. In that case, it is preferable that the resin for solidification is preliminarily contained in the unidirectional prepreg sheet layer 4 as the second fiber layer in the form of impregnation or coating.

[0015] 1(a) and (b), a unidirectional prepreg sheet layer 4 (second fiber layer) is positioned between braided layers 3 and 5 (first fiber layers) each produced from a carbon fiber intermediate body 2. In this case, for example, the braided layer 5 (first fiber layer) is first produced (woven) on a mandrel (FIG. 2) using a braiding device, and then, with the unidirectional prepreg sheet layer 4 (second fiber layer) placed therebetween, the outer braided layer 3 (first fiber layer) is produced using the braiding device.

[0016] The carbon fiber braided layers 3, 5 (first fiber layer) are braided, for example, into a cylindrical body having an endless shape in the circumferential direction from an intermediate body 2 made of thread-like or tape-like carbon fibers by a braiding device (FIG. 2). In this case, the intermediate body 2 constituting the braided layers 3, 5 (first fiber layer) is braided in a direction inclined to the axial direction of the cylindrical body. In this embodiment, at least one layer of the carbon fiber braided layer may be braided. For example, the inner braided layer 5 may be omitted, and the outer braided layer 3 may be braided with the unidirectional prepreg sheet layer 4 (second fiber layer) sandwiched on the mandrel.

[0017] As shown in FIG. 1(b), to position a unidirectional prepreg sheet layer 4 (second fiber layer) between carbon fiber braided layers 3 and 5 (first fiber layers), for example, first braid a small amount of the end of the outer peripheral braided layer 3 on the inner peripheral braided layer 5. Then, the tip of the carbon fiber material of the unidirectional prepreg sheet layer 4 is inserted there. If possible, a method may be used in which a required length of the outer peripheral braided layer 3 is braided on the inner peripheral braided layer 5, and then the carbon fiber material of the unidirectional prepreg sheet layer 4 is inserted from one end between the carbon fiber braided layers 3 and 5 (first fiber layers).

[0018] As described above, in this embodiment, when the cylindrical body 1 constituting the lens barrel part is manufactured from carbon fiber reinforced resin, the layer structure includes at least one layer of the braided layer (first fiber layer: 5, 3) of carbon fibers braided to have an endless form in the circumferential direction. That is, the braided layer (first fiber layer: 5, 3) of this embodiment is endless in the circumferential direction, and there is no seam of the carbon fiber layer that necessarily occurs in a structure in which only a one-directional prepreg sheet is wound around a mandrel as in the conventional structure. Therefore, there is no strength deterioration due to the seam of the carbon fiber sheet as in the conventional structure, and it is possible to configure a lens barrel part that is excellent in strength such as rigidity and impact resistance. In addition, since the braided layer (first fiber layer: 5, 3) can be braided in an endless form in the circumferential direction, the joint portion does not cause unevenness in the circumferential structure of the cylindrical body 1. For example, in the case of a cylindrical lens barrel part, a lens barrel part with excellent roundness can be obtained.

[0019] In this embodiment, when the cylindrical body 1 constituting the lens barrel part is manufactured from carbon fiber reinforced resin, at least one layer of braided layer (first fiber layer) of carbon fibers braided to form an endless form in the circumferential direction may be used. For example, in the example of Fig. 1 (a) and (b), the unidirectional prepreg sheet layer 4 is disposed between the braided layers 3 and 5, but the unidirectional prepreg sheet layer 4 may be omitted and the cylindrical body 1 may be formed of two braided layers 3 and 5. The braided layer 5 on the inner circumference side in Fig. 1 (a) and (b) may be changed to a unidirectional prepreg layer. Also, the unidirectional prepreg sheet layer 4 may be changed to a braided layer, in which case the cylindrical body 1 is formed by three braided layers. Also, one or several braided layers may be braided on the outer circumference of the braided layer 3.

[0020] The carbon fiber as the material of the unidirectional prepreg sheet layer 4 is a filament-like carbon fiber bundle or, for example, a rectangular carbon fiber sheet, which contains carbon fibers oriented in one direction, for example, substantially along the axial or circumferential direction of the cylindrical body 1. Preferably, carbon fibers oriented in the axial direction of the cylindrical body 1 are easier to handle during manufacturing, and may provide good strength to lens barrel components used in a nearly horizontal position. The unidirectional prepreg sheet layer 4 may be formed by arranging carbon fiber tapes separated into several pieces along the axial direction of the cylindrical body 1 along multiple axes. In this case, it is preferable that there are no gaps between the arranged tapes, but gaps may be present.

[0021] As described above, in this embodiment, in the cylindrical body 1 constituting the barrel component, in addition to the carbon fiber braided layers 3 and 5, a unidirectional prepreg sheet layer 4 containing fibers oriented in the axial direction of the cylindrical shape is disposed. This makes it possible to ensure strength and rigidity in the longitudinal direction, for example, in a long (large) and heavy photographic optical system with a long focal length.

[0022] To solidify the cylindrical body 1 into the finished shape of the lens barrel part, after the braiding process is completed, the mandrel or the layered structure of the cylindrical body 1 is reattached to another mold that corresponds to the finished shape, and then the resin is impregnated and solidified. For this resin solidification, a method such as heating with a heater or applying pressure with an autoclave is used. When sintering the resin for solidification, the shape may be regulated by applying pressure from the outside of the mandrel with another mold, if necessary.

[0023] For the resin impregnation and solidification, for example, a carbon fiber material that is pre-impregnated with a resin for solidification is used for the thread- or tape-shaped intermediate 2 of the braided cord layers 3 and 5, or the unidirectional prepreg sheet layer 4. Alternatively, a carbon fiber material that is not prepregged with a resin may be used for these layers, and the resin for impregnation and solidification may be applied later by coating or spraying.

[0024] After solidification, the molten and solidified resin distributes between the braided carbon fiber layers 3, 5 (first fiber layer) and the unidirectional prepreg sheet layer 4 (second fiber layer) to bond these layers together.

[0025] As the solidifying resin, for example, a thermoplastic resin such as polycarbonate can be used by impregnating the continuous carbon fibers of the braided layers 3 and 5 (first fiber layer) and the unidirectional prepreg sheet layer 4 (second fiber layer) in advance. Note that a thermoplastic resin is not necessarily an essential material for the solidifying resin, and those skilled in the art may change the solidifying resin to a thermosetting resin or a photocurable resin as necessary.

[0026] As a method for producing the resin-impregnated carbon fiber material, for example, in the case of the unidirectional prepreg sheet layer 4 (second fiber layer), a continuous carbon fiber sheet material having unidirectional orientation and a thermoplastic resin film are treated with a heated roll or the like to be integrated to obtain a prepreg sheet. The prepreg sheet can be cut into a thread or tape to produce the intermediate 2 for the braided layers 3 and 5 (first fiber layer). For example, a mixed fiber yarn obtained by mixing continuous carbon fiber and thermoplastic resin yarn may be used as the resin-impregnated carbon fiber material of the intermediate 2 for the braided layers 3 and 5 (first fiber layer). Also, the continuous carbon fiber may be impregnated by electrostatically attaching a thermoplastic resin powder to the continuous carbon fiber.

[0027] It is not particularly easy to impregnate the intermediate 2 with a thermoplastic resin so that no fine voids remain inside, and it is also necessary to give flexibility to the intermediate 2 when forming the braided layers 3 and 5, so the degree of impregnation of the thermoplastic resin into the continuous carbon fibers is preferably a semi-impregnated state. A preferred semi-impregnated state is one in which the density of the resin is, for example, about 40% to 70% of the theoretically void-free 100% impregnated state at the set VF (fiber volume fraction) value of the intermediate 2.

[0028] In the thermoplastic resin impregnation step, a sizing agent may be used to increase the affinity between the carbon fiber and the thermoplastic resin. For example, by attaching an epoxy emulsion sizing agent to the carbon fiber, the interfacial adhesion between the carbon fiber and the thermoplastic resin can be increased. In this case, the carbon fiber bundle is preferably opened so as to obtain good resin impregnation.

[0029] The cylindrical body 1 shown in Fig. 1(a) and (b) may be considered to have, for example, a cylindrical shape with a circular cross section, but the cylindrical shape is arbitrary. Any shape can be adopted, such as a cone shape, a cone shape in which the inclination angle of the cone shape changes in the axial direction, a horn shape, a constricted shape, or the like. The shape of the cylindrical body 1 is not limited to a cone shape, but may also have a pyramid shape, or the like. In a cone shape or a constricted shape in which the inclination angle changes in the axial direction, an R shape can be given to the point where the inclination angle changes.

[0030] In this embodiment, the thermoplastic resin with which the carbon fibers are pre-impregnated is polycarbonate. The impact resistance of polycarbonate itself improves the toughness of the cylindrical body 1, and a high-strength lens barrel component can be obtained. In applications such as this embodiment, the viscosity average molecular weight of polycarbonate as the thermoplastic resin for solidification is preferably in the range of approximately 18,000 to 25,000. If the viscosity average molecular weight of polycarbonate is 18,000 or less, the toughness decreases, and if it is 25,000 or more, the melt viscosity tends to be high, and there is a possibility that the impregnation property in the solidification (sintering) process decreases.

[0031] FIG. 2 shows the structure of a braiding device 6 that can be used in the braiding (braiding) process of the carbon fiber braid layers 3 and 5 in FIG. 1. In FIG. 2, the braiding device 6 has an annular frame 7 having a through hole 9. The mandrel 8 is inserted near the axial center of the through hole 9 of the annular frame 7 and positioned by a means not shown. The annular frame 7 has carriers 10 and 11 around which braided yarns 12 and 13 constituting the intermediate body 2 of the braided layers 3 and 5 are wound. The carriers 10 and 11 are driven by a driving means not shown to move around the annular frame 7 in opposite directions while moving on a figure-of-eight track 14 formed around a pipe body 15. As a result, the braided layers 3 and 5 of the cylindrical body 1 in FIG. 1 are braided from the braided yarns 12 and 13 by, for example, a braiding method. In FIG. 2, 16 shows a simplified illustration of a cylindrically braided fiber layer.

[0032] A bobbin (details not shown) is mounted in each of the carriers 10 and 11, and the braided yarns 12 and 13 of the intermediate body 2 are wound around the bobbin. Each of the carriers 10 and 11 also has a mechanism (details not shown) that generates tension by a spring force or the like to wind the braided yarns 12 and 13 around the mandrel 8. The movement directions of the carriers 10 and 11 are opposite to each other. That is, the carriers 10 and 11 move in opposite directions to each other along a figure-of-eight track 14 formed on the annular frame 7. A braided layer (3 to 5: FIG. 1) is formed on the mandrel 8 by the movement of the carriers 10 and 11.

[0033] For the sake of simplicity, only two sets of braids 12, 13 are shown in Fig. 2, but the corresponding braids are supplied from the adjacent sets of carriers 10, 11 on the annular frame 7 to the braiding position on the mandrel 8. In Fig. 2, the number of carriers 10, 11 on the annular frame 7 is assumed to be 36, but the number of carriers 10, 11 can be arranged corresponding to the number of braids required depending on the size and shape of the intended lens barrel parts. Note that a configuration may also be adopted in which a plurality of pipe bodies 15 are arranged in an annular shape on the annular frame 7, and braids are supplied from these pipe bodies 15 toward the mandrel 8 to form a cylindrically braided fiber layer 16.

[0034] The fiber layer 16 wound around the mandrel 8 and assembled into a cylindrical shape is heated using a heating means (heater, etc.) not shown, and if necessary, pressure is applied using an autoclave or the like to sinter and solidify the impregnated resin. At this time, molding pressure can be applied by pressing the outer mold or by the tension of the metal tape or the like. This sintering process advances the degree of impregnation of the carbon fiber and thermoplastic resin in the intermediate body 2, and then cooling, core removal from the mandrel 8, end cutting, etc. are performed to manufacture the cylindrical body 1 as a lens barrel component. In this embodiment, since a thermoplastic resin (polycarbonate) is used as the impregnated resin, there is an advantage that the sintering process time is short compared to, for example, a thermosetting resin, and productivity can be improved. In order to smoothly core the cylindrical body 1 from the mandrel 8, a release agent can be applied to the mandrel in advance, or a surface treatment such as hard Cr plating or polytetrafluoroethylene film formation can be performed.

[0035] 3(a) and (b) show a structure in which a ring-shaped resin part is provided as a covering part 17 at an end part 18 of the cylindrical body 1 as a lens barrel part configured as described above. The covering part 17 constitutes, for example, a mechanism or part thereof for fixing the cylindrical body 1 to another lens barrel part, or for attaching and detaching the cylindrical body 1 to another lens barrel part when the cylindrical body 1 is a lens hood or the like.

[0036] In the structure shown in Fig. 3(a) and (b), at least one end 18 of the cylindrical body 1 is covered with a resin part formed as a covering portion 17. The covering portion 17 can be formed, for example, by insert injection molding a thermoplastic resin. For example, the cylindrical body 1 manufactured as described above is inserted into an injection molding die, and a thermoplastic resin containing fibers is injection molded to form the covering portion 17, which is integrated with the cylindrical body 1. This insert molding process is shown in detail in Fig. 6 described later.

[0037] In order to obtain sufficient strength for use as a fixing portion or a detachable portion of a lens barrel component, the covering portion 17 is preferably made of a thermoplastic resin containing fiber. For example, polycarbonate can be used as the thermoplastic resin for the covering portion 17. In the case of polycarbonate, due to its excellent impact resistance, it is possible to obtain a lens barrel component having improved toughness in the mounting portion formed by the covering portion 17.

[0038] By forming the covering portion 17 on the end portion 18 of the cylindrical body 1, it is possible to provide a ring portion or the like for use as a fixing portion or a detachable portion on the lens barrel component, which cannot be created by the braiding or solidification process of the cylindrical body 1. In addition, by using a thermoplastic resin containing fiber, it is possible to maintain the strength of the attachment portion or the like formed by the covering portion 17. The fiber referred to here is not particularly limited as long as it is fibrous, but is generally short-fiber glass fiber or carbon fiber or both with a length of 1 mm or less. In this case, the fiber content is not particularly limited, but is preferably in the range of about 20% to 40%.

[0039] The covering portion 17 can be molded into any shape and size according to the performance, specifications, dimensions, etc. required for use as a fixing portion or a detachable portion of a lens barrel component. In the structure of Figs. 3(a) and (b), the covering portion 17 is molded so as to cover the circumference of one end portion 18 of the cylindrical body 1, and a flange portion 17a protruding in the inner circumferential direction is formed on the inside of the end portion 18. When the cylindrical body 1 is the body of a lens barrel, the flange portion 17a is used as a support portion for an optical element or a focus ring. Also, for example, when the cylindrical body 1 is a lens hood that is detachable from the main body of a photographic optical system, the resin part configured as the covering portion 17 can be used as a part of a mechanism for attaching and detaching the lens hood.

[0040] Figures 4(a), (b), and (c) show different structures for providing a ring-shaped resin part as a covering part 17 on the end part 18 of the cylindrical body 1 as a lens barrel part configured as described above. Figures 4(a) and (b) are plan views and cross-sectional views in the same format as Figures 3(a) and (b), and Figure 4(c) is a cross-sectional view showing an enlarged view of the circled part in Figure 3(b).

[0041] In Fig. 4, 20 is a circumscribing circle consisting of the thickest part of the cylindrical body 1, and the diameter of this peripheral surface is a diameter φ. The configuration in Fig. 4 differs from Fig. 3 in that, as shown in a particularly enlarged view in Fig. 4(c), the peripheral surface of the covering part 17 as a resin part is located inside the peripheral surface (circumscribing circle 20) of the cylindrical body 1, and this portion becomes an exposed part 21 of the end part 18 of the cylindrical body 1. The exposed amount 22 of the exposed part 21, i.e., the distance between the peripheral surface of the covering part 17 and the peripheral surface (circumscribing circle 20) of the cylindrical body 1, is set to a distance greater than the thickness distribution occurring during the braiding of the braided layers 3 and 5 described below, that is, at least 0.1 mm or more.

[0042] The reason for adopting such a structure is to perform good insert molding of the covering portion 17. For example, when the braided layers 3 and 5 are braided, unevenness occurs in the overlapping portion of the intermediate body 2, resulting in a distribution of thick and thin portions in the tubular body 1. For example, in the process of winding the fiber layer 16 around the mandrel 8 in FIG. 2, gaps tend to occur more easily between the braided threads of the intermediate body 2 in the braided layer 3 of the mandrel 8 than in the braided layer 5 on the inner side of the mandrel 8. In the case of a standard carbon fiber material, this variation in thickness of the tubular body 1 occurs by about 0.1 mm at the height of the circumferential surface of the tubular body 1.

[0043] Due to the characteristics of the braided layers 3 and 5, a part of the outer circumferential surface of the cylindrical body 1 is formed with a thinner thickness than the other parts. When the cylindrical body 1 is set in an injection mold for insert molding of the covering portion 17, a gap is generated between the cylindrical body 1 and the mold at the part of the outer circumferential surface where the thickness is thin. For example, as shown in FIG. 3, in a structure in which the exposed portion 21 does not exist at the end 18 of the cylindrical body 1, the cavity for the covering portion 17 and the gap between the mold at the part of the outer circumferential surface of the cylindrical body 1 where the thickness is thin are connected. Therefore, when the resin of the covering portion 17 is injected into the cavity, the thermoplastic resin may enter the gap between the outer circumferential surface of the cylindrical body 1 and the mold, and burrs may be generated on the outer circumferential surface near the end 18 of the cylindrical body 1. In particular, if burrs are generated on the outer circumferential surface of the cylindrical body 1 used as a lens barrel part, the appearance quality of the lens barrel part will be deteriorated.

[0044] In response to this, as shown in FIG. 4, the shape of the covering portion 17 is determined so that the exposed portion 21 is formed at the end 18 of the cylindrical body 1 with an exposed amount 22 equal to or greater than the amount of thickness distribution (0.1 mm), and an injection molding die for insert molding the covering portion 17 is formed. As a result, even if there is variation in the thickness distribution of the peripheral surface of the end 18 of the cylindrical body 1 caused by the braiding of the braid layers 3 and 5, the exposed amount 22 of the exposed portion 21 is set to be greater than that. Therefore, the die reliably seals the edge portion 19 (FIG. 4(c)) of the peripheral surface of the end 18 of the cylindrical body 1 so that resin does not get into the peripheral surface. As a result, compared to the structure without the exposed portion 21 of FIG. 3, burrs caused by insert molding of the covering portion 17 on the peripheral surface of the end 18 of the cylindrical body 1 can be effectively suppressed. Therefore, it is possible to manufacture a lens barrel part with good dimensional accuracy and beautiful appearance.

[0045] <Embodiment 2> Below, a modified example of the first embodiment will be described with reference to Figures 7(a), (b) and (c). Below, the same reference numerals are used for the same or equivalent configurations as those described above, and detailed description thereof will be omitted unless otherwise necessary. Figures 7(a) and (b) respectively show the side and cross section of a cylindrical body 1 having a completed covering portion 17, and Figure 7(c) shows in detail the cross section of the part circled in Figure 7(b).

[0046] 7, the covering portion 17 is also formed by insert injection molding of a thermoplastic resin, for example. For example, the cylindrical body 1 is inserted into a die for injection molding, and a thermoplastic resin containing fibers is injected to form the covering portion 17, which is integrated with the cylindrical body 1. This insert molding process is shown in detail in FIG. 8, which will be described later.

[0047] This embodiment is characterized in that a resin layer 40 is formed on the surface of the cylindrical body 1. In FIG. 7(c), 40 denotes the resin layer of this embodiment, and 41 in the figure denotes an extremely thin resin layer with a very small thickness. This extremely thin resin layer 41 originates from the intermediate body 2 constituting the braided cord layers 3 and 5. That is, the extremely thin resin layer 41 of 5 to 15 μm is formed on the surface layer of the cylindrical body 1 through a solidification process by the resin that is pre-impregnated in the intermediate body 2. This extremely thin resin layer 41 has the role of preventing strength deterioration caused by the carbon fiber material being exposed on the outer surface.

[0048] However, this very thin resin layer 41 is relatively fragile, and there is a concern that this may affect the bonding strength between the cylindrical body 1 and the covering portion 17. For example, it is conceivable that the very thin resin layer 41 may be divided due to the intrusion of carbon fibers that are unable to completely cover the very thin resin layer 41, resulting in a deterioration in the bonding strength. In this regard, by providing the resin layer 40, the divisions in the very thin resin layer 41 can be filled, and the deterioration in the bonding strength can be prevented.

[0049] Also, for example, when the adhesion between the ultrathin resin layer 41 and the carbon fiber is insufficient, the bonding strength may deteriorate. In this regard, by providing the resin layer 40, the heat insulating effect causes heat storage from the resin during injection molding when forming the covering portion 17, and increases the activation energy between the ultrathin resin layer 41 and the carbon fiber. Then, the pressure when forming the covering portion 17 can be used to firmly bond the ultrathin resin layer 41 and the carbon fiber.

[0050] In this case, in order to utilize the heat insulating effect, the thickness of the resin layer 40 needs to be 50 μm or more and 200 μm or less. If the thickness of the resin layer 40 is 50 μm or less, the heat insulating effect cannot be exhibited, and heat from the resin escapes to the mold side through the cylindrical body 1, and the desired temperature rise cannot be expected between the ultra-thin resin layer 41 and the carbon fiber. Furthermore, if the thickness is 200 μm or more, the resin layer 40 is too thick, and due to its own heat capacity, the desired temperature rise cannot be expected between the ultra-thin resin layer 41 and the carbon fiber. Furthermore, if the thickness is 200 μm or more, it is not suitable from the viewpoint of weight reduction, which is the original purpose.

[0051] Considering the above, a thermoplastic resin such as polycarbonate is used as the resin for the resin layer 40. Also, considering the insert molding process of the covering portion 17, the resin layer 40 and the covering portion 17 are preferably made of resins that have a high affinity with each other, and in particular, are preferably made of the same resin. Also, it is desirable that the resin layer 40 and the resin previously impregnated in the intermediate body 2 constituting the braided layers 3 and 5 have a high affinity with each other, and are preferably made of the same resin. By using such a combination of materials, the bonding strength between the resin layer 40 and the covering portion 17 and the extremely thin resin layer 41 can be increased.

[0052] In this embodiment, the resin layer 40 is made of polycarbonate. In applications such as this embodiment, the viscosity average molecular weight of this polycarbonate is preferably in the range of about 18,000 to 25,000. For example, if the viscosity average molecular weight of polycarbonate is 18,000 or less, the toughness tends to decrease, and if it is 25,000 or more, the melt viscosity tends to increase, and there is a possibility that the bonding strength between the resin layer 40 and the ultrathin resin layer 41 will deteriorate during the impregnation process.

[0053] As a method for forming the resin layer 40, for example, a film-like thermoplastic resin that will become the resin layer 40 is wound around the fiber layer 16 in which the intermediate body 2 is assembled in a cylindrical shape in advance. Then, the intermediate body 2 and the wrapped thermoplastic resin are heated (and pressurized as necessary) to form the extremely thin resin layer 41 of 5 to 15 μm on the surface layer of the cylindrical body 1 and the resin layer 40. As a method for winding the film-like thermoplastic resin, for example, after the fiber layer 16 in which the intermediate body 2 is assembled in a cylindrical shape is manufactured, a winding method is given in which a filament of a thermoplastic resin processed from a film into a tape shape is filament-wound. In addition, as another method, for example, a method may be used in which, after the fiber layer 16 in which the intermediate body 2 is assembled in a cylindrical shape is manufactured, the thermoplastic resin of the film in a tape shape is braided to wind it around the fiber layer 16 in which the intermediate body 2 is assembled in a cylindrical shape.

[0054] As another method, after manufacturing a cylindrical body 1 having a 5 to 15 μm ultrathin resin layer 41 formed on the surface layer, a filament of a thermoplastic resin processed from a film into a tape shape is filament-wound and wound on the ultrathin resin layer 41. Then, after winding, the thermoplastic resin is heated (and pressurized as necessary) to form a resin layer 40 on the 5 to 15 μm ultrathin resin layer 41 on the surface layer of the cylindrical body 1.

[0055] As another method, for example, after manufacturing a tubular body 1 with a 5 to 15 μm ultrathin resin layer 41 formed on the surface layer, a tape-shaped thermoplastic resin film is wound around the tubular body 1 by weaving it onto the ultrathin resin layer 41. Then, after winding, the thermoplastic resin is heated (and pressurized as necessary) to form a resin layer 40 on the 5 to 15 μm ultrathin resin layer 41 on the surface layer of the tubular body 1.

[0056] Thereafter, the cylindrical body 1 on which the resin layer 40 has been formed is inserted into a mold, and the covering portion 17 is formed on the resin layer 40 by injection molding to be integrated. Alternatively, a method may be used in which a film that will become the resin layer 40 is wound to a specified thickness or more, and after the resin layer 40 is formed, the resin layer 40 is shaved to the specified thickness.

[0057] In the case where the surface of the cylindrical body 1 is uneven due to the assembly of the intermediate body 2, for example, when applying a coating for the purpose of heat insulation to the lens barrel parts, the appearance quality may be reduced. However, as in this embodiment, the resin layer 40 is formed by wrapping a film that becomes the resin layer 40 with a thickness of 50 μm or more and 200 μm or less, or by further cutting the resin layer 40 to a specified thickness, the resin layer 40 other than the coating part 17 to be coated can be finished smoothly. This can significantly improve the appearance quality of the coating. It is also possible to adopt a method in which the resin layer 40 is formed with a specified thickness only in the area where the coating part 17 is formed, and the other resin layer 40 is cut to a specified thickness or less. This can maintain the thickness of the resin layer 40 due to the bonding strength, while smoothing the other appearance quality parts by cutting them, and also contribute to weight reduction.

[0058] <Example 1> Figures 5(a), (b), and (c) show the configuration of the covering portion 17 which is further modified from Figures 4(a), (b), and (c). Figures 6(a) to (d) show the state of insert molding of the covering portion 17 into the cylindrical body 1. Below, the configuration of the cylindrical body 1 and the details of the manufacturing process will be described in detail with reference to Figures 5 and 6.

[0059] In Fig. 5(a), 23 indicates the braiding angle of the intermediate body 2 constituting the braided layer (3 or 5). In other words, the intermediate bodies 2 constituting the braided layers 3 and 5 are braided in a direction inclined at the braiding angle 23 to the axial direction of the tubular body. As shown in Fig. 5(b) or (c), the layered structure of the tubular body 1 is a three-layer configuration of the braided layer 3, unidirectional prepreg sheet layer 4, and braided layer 5 from the inner periphery, as described above.

[0060] The intermediate 2 for braiding the braided layer (3 or 5) is, for example, a prepreg sheet cut into a tape shape, which is made by electrostatically attaching thermoplastic resin powder to an opened carbon fiber sheet material and heating it. The sheet material for the unidirectional prepreg sheet layer 4 is, for example, wrapped around the braided layer 5 before braiding the third braided layer 3, and is positioned between the layers as the braided layer 3 is braided.

[0061] Moreover, the VF of the intermediate 2 of the braided layer (3 or 5) and the unidirectional prepreg sheet are both set to, for example, 50%, and the impregnated resin for both is polycarbonate with a viscosity average molecular weight of 20,000. The theoretical thickness of the intermediate 2 when 100% impregnated is 0.115 mm, and the density of the thermoplastic resin in the semi-impregnated state of the intermediate 2 when the braided layers 3 and 5 are formed is set to 50% to 60%. The cylindrical body 1, which is made of three layers of the braided layer 3, the unidirectional prepreg sheet layer 4, and the braided layer 5 made of such materials and manufactured by the process described below, is assumed to have a theoretical thickness of about 0.575 mm (Table 1 below).

[0062] The braiding angle 23 of the intermediate body 2 and the orientation direction of the carbon fibers in the unidirectional prepreg sheet are determined taking into consideration the strength, rigidity, etc. in the completed state in which it is used as a lens barrel part. For example, different braiding angles (23) may be used, such as a braiding angle of 30° for the inner braided layer 3 and a braiding angle of 60° for the outer braided layer 5. The orientation direction of the carbon fibers in the unidirectional prepreg sheet is made to approximately coincide with the direction along the cylindrical axis of the tubular body 1.

[0063] The cylindrically assembled fiber layer 16 (FIG. 2) braided on the mandrel 8 using the braiding device 6 in FIG. 2 (first step) is heated using a heating means (such as an autoclave, not shown) to solidify the thermoplastic resin impregnated therein (second step). Although it depends on the specifications of the lens barrel components that constitute the cylindrical body 1, for example, a cylindrical mandrel 8 having a diameter of about Φ69 mm is used. In addition, the mandrel 8 is subjected to a surface treatment, such as polytetrafluoroethylene plating, for easy release.

[0064] In the solidification process, molding pressure is applied from the outer periphery of the cylindrically assembled fiber layer 16. For example, applying pressure by the tension of wrapping a metal tape can promote the impregnation, bonding, and solidification of the carbon fibers and thermoplastic resin in the intermediate body 2. In the solidification process, it is also possible to form the final shape of the cylindrical body 1 (for example, a truncated pyramid shape) using inner and outer molds of different shapes from the mandrel 8.

[0065] Thereafter, the mandrel 8 and the cylindrical body 1 are cooled, the cylindrical body 1 is removed from the mandrel 8, and the end portion 18 is appropriately cut and shaped to complete the cylindrical body 1.

[0066] The properties of the cylindrical bodies manufactured under the above conditions and comparative examples are shown in Table 1. Table 1 shows the results of compression tests conducted in the cylindrical axial direction on the cylindrical bodies manufactured under the above conditions (left side of Table 1: Examples) and the cylindrical bodies (right side of Table 1: Comparative Examples).

[0067] [Table 1]

[0068] The cylindrical body of the embodiment (left side of Table 1) is composed of the braided layers 3 and 5 and the unidirectional prepreg sheet layer 4 (FIGS. 5(b) and 5(c)). The cylindrical body of the comparative example (right side of Table 1) is made by repeatedly laminating and solidifying six layers of unidirectional prepreg sheets impregnated with hydrogenated bisphenol A epoxy resin while changing the orientation direction of the fibers in the cylindrical axial direction and circumferential direction of the cylindrical body. The cylindrical body of the comparative example (right side of Table 1) is different from that of the above-mentioned embodiment in that it does not use a cylindrical braided layer and is formed by winding a unidirectional prepreg sheet. The theoretical thickness of the cylindrical body of the comparative example (right side of Table 1) is 0.84 mm. In contrast, the theoretical thickness of the cylindrical body of the embodiment (left side of Table 1) is 0.575 mm, which is thin and therefore lightweight. Moreover, the cylindrical body of the embodiment (left side of Table 1) is thinner than the cylindrical body of the comparative example (right side of Table 1), but it can achieve a compressive fracture strength equal to or greater than that of the comparative example.

[0069] In the following, with reference to Fig. 6, a configuration in which a resin part is insert-molded as the covering part 17 on the end part 18 of the cylindrical body 1 that has undergone the solidification process, and an example of the insert molding process will be described in detail. Here, as described in Fig. 5, the covering part 17 is formed having an exposed part 21 with an exposure amount 22 from a circumscribed circle 20 consisting of the maximum thickness part being 0.1 mm. In this example, as shown in Figs. 5(b) and (c), the edge part 19 on the end part 18 of the cylindrical body 1 is lightly chamfered to 0.05 mm or less. The chamfering of this edge part 19 can be formed, for example, by cutting before the covering part 17 is insert-molded.

[0070] 6(a) to (d) show cross sections of a mold for insert-molding a resin part as a covering part 17 onto an end part 18 of a cylindrical body 1 that has been through a solidification process, in the order of steps. In Fig. 6(a) to (d), an insert-molding mold 24 is made up of a fixed mold 25 and a movable mold 26, and is mounted on an injection molding machine 30.

[0071] As shown in Figs. 6(a) and 6(b), the fixed die 25 and the movable die 26 have a cavity 28 formed therein to accommodate the solidified cylindrical body 1. As shown in Fig. 6(a), the solidified cylindrical body 1 is accommodated in the cavity 28, and the mold is clamped as shown in Fig. 6(b). In this state, a mold shape 27 for molding the covering portion 17 is provided at a position of the fixed die 25 corresponding to the end portion 18 of the cylindrical body 1, with a structure as shown in Figs. 5(b) and 5(c). This mold shape 27 is shaped to seal the end edge of the cylindrical body 1 in the fixed die 25 so that the exposed portion 21 is formed. This mold shape 27 can effectively prevent the resin from overflowing from the cavity 28 on the inner periphery side of the end portion 18 of the cylindrical body 1 toward the outer periphery of the cylindrical body 1 to become a burr when the molding resin 32 is poured as shown in Fig. 6(c).

[0072] In the insert molding process of the covering portion 17, first, the cylindrical body 1 is set in the cavity 28 of the movable die 26 of the insert molding die 24 as shown in Figure 6(a), and then the fixed die 25 and the movable die 26 of the insert molding die 24 are clamped together as shown in Figure 6(b).

[0073] Further, as shown in FIG. 6(c), the injection molding machine 30 injects and fills the molten molding resin 32 through the spool, runner, and gate (31: FIG. 6(a)) of the insert molding die 24. At that time, in this embodiment, the fixed die 25 seals the end 18 so that the exposed portion 21 is formed at the end 18 of the cylindrical body 1 by the mold shape 27, so that the molding resin 32 can be prevented from leaking from the cavity 28 toward the outer periphery of the cylindrical body 1 and becoming a burr. For example, polycarbonate containing 30% glass fiber is used as the molding resin 32. After that, the molding resin 32 is hardened through mold cooling or the like, so that the cylindrical body 1 and the molding resin 32 are integrated, and the above-mentioned ring- and flange-shaped covering portion 17 can be formed at the end 18 of the cylindrical body 1.

[0074] Thereafter, the injection molding machine 30 is driven to separate the fixed mold 25 and the movable mold 26 as shown in Fig. 6(d), and a demolding means (not shown) demolds the cylindrical body 1 and the portion of the runner 33 molded within the gate by the molding resin 32. In this manner, it is possible to manufacture a lens barrel part consisting of the cylindrical body 1 equipped with a resin part (coating portion 17), which has a high-quality appearance without burrs on the outer periphery.

[0075] <Example 2> As another example, the configuration and manufacturing process of the cylindrical body 1 described as the second embodiment will be described in detail with reference to Figs.

[0076] 7(b) or (c), the laminated structure of the cylindrical body 1 is, as described above, a three-layer structure consisting of, from the inner periphery, a braided layer 3, a unidirectional prepreg sheet layer 4, and a braided layer 5. The intermediate body 2 for braiding the braided layer (3 or 5) is made, for example, of a prepreg sheet produced by electrostatically attaching thermoplastic resin powder to an opened carbon fiber sheet material and heating it, and then cutting the prepreg sheet into a tape shape.

[0077] The sheet material for the unidirectional prepreg sheet layer 4 is, for example, wrapped around the braided layer 5 before the third braided layer 3 is braided, and is positioned between the layers while the braided layer 3 is being braided. The VF of the intermediate 2 of the braided layer (3 or 5) and the unidirectional prepreg sheet are both, for example, 50%, and the impregnating resin for both is polycarbonate with a viscosity average molecular weight of 20,000.

[0078] The theoretical thickness of intermediate body 2 when 100% impregnated is 0.115 mm, and the density of the thermoplastic resin in the semi-impregnated state of intermediate body 2 when braided layers 3 and 5 are formed is set to 50% to 60%. The theoretical thickness of tubular body 1, which is made of three layers of braided layer 3, unidirectional prepreg sheet layer 4, and braided layer 5 made of such materials and manufactured by the process described below, is expected to be approximately 0.575 mm.

[0079] Using the braiding device 6 of FIG. 2, a cylindrically braided fiber layer 16 (FIG. 2) is produced by braiding (first step) on a mandrel 8.

[0080] Next, a tape-like polycarbonate film is placed on one of the carriers 10 in the braiding device 6, and filament winding is performed to wind the polycarbonate film around the cylindrically assembled fiber layer 16.

[0081] The polycarbonate film used was slit into a width of 5 mm in advance and had a viscosity average molecular weight of 20,000.

[0082] Next, the cylindrically assembled fiber layer 16 wrapped with the polycarbonate film is heated by a heating means to solidify the impregnated thermoplastic resin (second process). Although it depends on the specifications of the lens barrel components that constitute the cylindrical body 1, for example, a cylindrical mandrel 8 with a diameter of about Φ69 mm is used. In addition, the mandrel 8 is subjected to a surface treatment, such as polytetrafluoroethylene plating, for easy release.

[0083] In the solidification process, molding pressure is applied from the outer periphery of the polycarbonate film wrapped around the cylindrically assembled fiber layer 16. For example, by applying pressure by the tension of wrapping a metal tape, the carbon fibers and thermoplastic resin in the intermediate 2 can be impregnated, bonded, and solidified, and integrated with the polycarbonate film wrapped around the surface.

[0084] Thereafter, the mandrel 8 and the cylindrical body 1 are cooled, the cylindrical body 1 is then de-cored from the mandrel 8, and the end portion 18 is appropriately cut and shaped to complete the cylindrical body 1 with a resin layer 40 formed on the surface.

[0085] At that time, the resin layer 40 on the surface was made to have a predetermined thickness by grinding. Below, with reference to Fig. 8, a configuration in which a resin part is insert-molded as the covering part 17 into the resin layer 40 on the surface of the cylindrical body 1 that has been subjected to the solidification process, and an example of the insert molding process will be described in detail.

[0086] Here, the thickness 42 of the covering portion 17 shown in Fig. 7 is set to 1.5 mm. Figs. 8(a) to (d) show, in the order of steps, cross sections of a mold for insert-molding a resin part as the covering portion 17 into the resin layer 40 on the surface of the cylindrical body 1 that has been through the solidification step. In Figs. 8(a) to (d), the insert-molding mold 24 is made up of a fixed mold 25 and a movable mold 26, and is mounted on an injection molding machine 30.

[0087] As shown in Figures 8(a) and 8(b), a cavity 28 is formed in the fixed die 25 and the movable die 26 to accommodate the solidified cylindrical body 1. As shown in Figure 8(a), the solidified cylindrical body 1 is accommodated in this cavity 28, and the die is clamped as shown in Figure 8(b). In this state, a die shape 27 for molding the covering portion 17 is provided.

[0088] In the insert molding process of the covering portion 17, first, the cylindrical body 1 on which the resin layer 40 has been formed is set in the cavity 28 of the movable die 26 of the insert molding die 24 as shown in Fig. 8(a), and then the fixed die 25 and the movable die 26 of the insert molding die 24 are clamped as shown in Fig. 8(b). Furthermore, as shown in Fig. 8(c), the molding resin 32 in a molten state is injected and filled through the spool, runner, and gate (31: Fig. 8(a)) of the insert molding die 24.

[0089] The molding resin 32 is made of, for example, polycarbonate containing 30% glass fiber. Thereafter, the molded resin 32 is hardened after cooling the mold, etc., whereby the cylindrical body 1 and the molded resin 32 are integrated, and the covering portion 17 as described above can be formed on the resin layer 40 of the cylindrical body 1.

[0090] Thereafter, the injection molding machine 30 is driven to separate the fixed mold 25 and the movable mold 26 as shown in Fig. 8(d), and a demolding means (not shown) demolds the cylindrical body 1 and the portion of the runner 33 molded within the gate by the molding resin 32. In this manner, a lens barrel part consisting of the cylindrical body 1 equipped with a resin part (coating portion 17) is obtained. Thereafter, by painting the surface, a lens barrel part with a high-quality appearance can be manufactured.

[0091] In addition, for a given thickness of the resin layer 40, since the actual strength relative to the thickness cannot be measured in the form of the cylindrical body 1, a tensile test was performed to confirm the joining strength. Figures 9(a) to (c) show the shapes of the samples used in this tensile test. Figure 9(a) is a plan view of the sample, Figure 9(b) is a cross-section of the joint, and Figure 9(c) shows the cross-sectional structure of the circled part in Figure 9(b) in detail. In Figures 9(a) to (c), 50 is an experimental piece, 51 is a continuous carbon fiber reinforced resin molded body provided with the resin layer 40 (Figures 9(b) and 9(c)), and 52 and 53 are the length and width of the continuous carbon fiber reinforced resin molded body 51. In addition, 54 and 55 in the figures are the length and width of the covering part 17, and 56 and 57 in the figures are the length and width of the joint between the continuous carbon fiber reinforced resin molded body 51 and the covering part 17.

[0092] Here, the lengths 52 and 54 are both 75 mm, and the widths 53 and 55 are both 25 mm. The length 56 of the joint is 25 mm, and the width 57 is 25 mm. The laminated structure of the continuous carbon fiber reinforced resin molded body 51 is a three-layer structure consisting of a twill layer 58, a unidirectional prepreg sheet layer 59, and a twill layer 60. The VF of the twill layer (58 or 60) and the unidirectional prepreg sheet is, for example, both 50%, and the impregnated resin in both is polycarbonate with a viscosity average molecular weight of 20,000. The theoretical thickness of the intermediate body 2 when 100% impregnated is 0.115 mm, and the density of the thermoplastic resin in the semi-impregnated state of the intermediate body 2 when the twill layers 58 and 60 are formed is set to 50% to 60%.

[0093] The continuous carbon fiber reinforced plastic molding 51, which is composed of three layers of twill layer 58, unidirectional prepreg sheet layer 59, and twill layer 60 made of such materials and is manufactured by the process described below, is expected to have a theoretical thickness of approximately 0.575 mm.

[0094] The twill layer was prepared by twill-weaving the intermediate 2, and a unidirectional prepreg sheet layer 59 was disposed between the twill layers 58 and 60, and a polycarbonate film was laminated on the twill layer 58 side. The viscosity average molecular weight of the polycarbonate film was 20,000.

[0095] Next, the continuous carbon fiber reinforced resin molded body 51 laminated with the polycarbonate film is heated by a heating means to solidify the thermoplastic resin in the impregnated state (second step). In this solidification step, a molding pressure is applied to the continuous carbon fiber reinforced resin molded body 51 by using a flat mold and a press device (not shown).

[0096] By applying pressure, the carbon fibers and thermoplastic resin in the intermediate body 2 can be impregnated, bonded, and solidified, and the carbon fibers and thermoplastic resin can be integrated with the polycarbonate film laminated on the surface. Thereafter, the mold and the continuous carbon fiber reinforced resin molded body 51 are cooled, and then the mold is released and cut to complete the continuous carbon fiber reinforced resin molded body 51 having the surface resin layer 40. At this time, the surface resin layer 40 is processed to a predetermined thickness by grinding.

[0097] Thereafter, a resin part was insert-molded as a covering part 17 into the resin layer 40 on the surface of the continuous carbon fiber reinforced resin molded body 51 that had been subjected to the solidification process, thereby producing an experimental piece 50 as shown in Fig. 9. Here, the thickness of the covering part 17 shown in Fig. 9 was set to 1.5 mm.

[0098] The characteristics of the bonding strength depending on the thickness of the resin layer 40 of the continuous carbon fiber reinforced resin molded body 51 manufactured under the above conditions are shown in Table 2 below. This Table 2 shows the results of a tensile test performed on the test piece 50 (Example) manufactured under the above conditions. At this time, an electromechanical universal material testing machine manufactured by Instron was used, and both ends of the test piece 50 were chucked by the testing machine at 25 mm, and a tensile test was performed. In Table 2, the thickness of the resin layer 40 is a value obtained by subtracting the thickness dimension calculated from the theoretical thickness of the continuous carbon fiber reinforced resin molded body without the resin layer 40 from the thickness dimension of the continuous carbon fiber reinforced resin molded body 51 in which the resin layer 40 is actually included.

[0099] [Table 2]

[0100] As shown in Table 2, if the thickness of the resin layer 40 is 50 μm to 200 μm, a tensile strength of 5 MPa or more can be obtained. It is also found that a structure in which the resin layer 40 having a thickness of 50 μm to 200 μm is provided on the surface of the cylindrical body is preferable. With such a structure, a lens barrel part with excellent bonding strength can be obtained. [Explanation of symbols]

[0101] DESCRIPTION OF THE REFERENCE NUMERALS 1...tubular body, 2...intermediate body, 3, 5...braided layer, 4...unidirectional prepreg sheet layer, 6...braiding device, 7...annular frame, 8...mandrel, 9...through hole, 10, 11...carrier, 12, 13...braided thread, 14...figure-of-eight track, 15...pipe body, 17...covering portion, 18...end portion, 19...edge portion, 20...circumscribed circle, 21...exposed portion, 22...exposed amount, 23...braiding angle, 24...insert molding die, 25...fixed die, 26...movable die, 28...cavity, 40...resin layer, 41...ultrathin resin layer.

Claims

1. An optical device configured to be detachably attached to an imaging device, a cylindrical body including a first carbon fiber layer which is a cylindrically braided layer, and a cylindrical second carbon fiber layer which is located on the outer circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer and the second carbon fiber layer being bonded together by a thermoplastic resin which is an integrated combination of a first thermoplastic resin impregnated into the first carbon fiber layer and a second thermoplastic resin impregnated into the second carbon fiber layer; an optical element; The first carbon fiber layer is provided so that the carbon fibers of the first carbon fiber layer are inclined with respect to the axial direction of the cylindrical body and woven in a twill pattern, and are endless in the circumferential direction of the cylindrical body, The second carbon fiber layer is a sheet-shaped carbon fiber layer. An optical instrument characterized by:

2. An optical device configured to be detachably attached to an imaging device, a cylindrical body including a first carbon fiber layer which is a cylindrically braided layer, and a cylindrical second carbon fiber layer located on the inner circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer and the second carbon fiber layer being bonded together by a thermoplastic resin in which a first thermoplastic resin impregnated in the first carbon fiber layer and a second thermoplastic resin impregnated in the second carbon fiber layer are integrated; an optical element; The first carbon fiber layer is provided so that the carbon fibers of the first carbon fiber layer are inclined with respect to the axial direction of the cylindrical body and woven in a twill pattern, and are endless in the circumferential direction of the cylindrical body, The second carbon fiber layer is a sheet-shaped carbon fiber layer. An optical instrument characterized by:

3. The cylindrical body is formed by integrally bonding the first carbon fiber layer impregnated with the first thermoplastic resin and the second carbon fiber layer impregnated with the second thermoplastic resin by heat treatment under pressure using an outer mold.

3. The optical device according to claim 1 or 2.

4. The second carbon fiber layer is a sheet-shaped carbon fiber layer along the circumferential direction of the cylindrical body, the sheet-shaped carbon fiber layer being provided so as to have a seam in the circumferential direction of the cylindrical body.

4. An optical instrument according to claim 1, wherein the optical instrument is a casing.

5. A first resin layer having a thickness of 5 μm to 15 μm is provided on a side of the second carbon fiber layer opposite to the first carbon fiber layer and on a side of the first carbon fiber layer opposite to the second carbon fiber layer, 5. An optical instrument according to claim 1, wherein the optical instrument is a casing.

6. The carbon fibers of the second carbon fiber layer are oriented in the axial direction of the cylindrical body, and do not include any carbon fibers inclined with respect to the axial direction of the cylindrical body.

6. An optical instrument according to claim 1, wherein the optical instrument is a casing.

7. a third carbon fiber layer which is a cylindrical braided layer located on the opposite side of the second carbon fiber layer from the first carbon fiber layer, and the second carbon fiber layer and the third carbon fiber layer are bonded to each other by a resin; 7. An optical instrument according to claim 1, wherein the optical instrument is a casing.

8. The carbon fibers of the third carbon fiber layer are arranged at an angle to the axial direction of the cylindrical body.

8. An optical instrument according to claim 7.

9. A braiding angle of the carbon fibers in the first carbon fiber layer with respect to the axial direction of the tubular body is different from a braiding angle of the carbon fibers in the third carbon fiber layer with respect to the axial direction of the tubular body.

9. An optical instrument according to claim 7 or 8.

10. the third carbon fiber layer being a twill layer; 10. Optical instrument according to claim 7, characterized in that

11. A ring-shaped resin coating portion is attached to an end of the cylindrical body.

11. An optical instrument according to claim 1 .

12. The resin of the coating portion is a thermoplastic resin containing fibers.

12. The optical instrument according to claim 11.

13. The peripheral surface of the cylindrical body is located 0.1 mm or more inside the peripheral surface of the covering portion, and the end of the cylindrical body forms an exposed portion exposed from the covering portion in that portion.

13. An optical instrument according to claim 11 or 12.

14. The thermoplastic resin is polycarbonate.

14. Optical instrument according to any one of claims 1 to 13.

15. The optical element includes at least one of a lens or a mirror.

15. Optical instrument according to any one of claims 1 to 14.

16. The cylindrical body constitutes a body part of a lens barrel that holds or adjusts an optical element.

16. Optical instrument according to any one of claims 1 to 15.

17. 17. The optical device according to claim 1, wherein the cylindrical body is a lens barrel part constituting at least one of a lens hood, an outer tube, an inner tube, and a focus ring, which is configured to be detachable from the imaging device.

18. forming a first carbon fiber layer impregnated with a first thermoplastic resin by crossing and braiding a plurality of carbon fibers on a mandrel into a cylindrical shape; forming a second layer of carbon fiber on the mandrel, the second layer being impregnated with a second thermoplastic resin; and bonding the first carbon fiber layer and the second carbon fiber layer with a thermoplastic resin by heat treating the first carbon fiber layer and the second carbon fiber layer. The bonding step is carried out under pressure using an outer mold, In the step of forming the first carbon fiber layer, the first carbon fiber layer is provided so that the carbon fibers of the first carbon fiber layer are woven in a twill pattern inclined with respect to the axial direction of the cylindrical body and are endless in the circumferential direction of the cylindrical body, A method for manufacturing a cylindrical body, wherein in the step of forming the second carbon fiber layer, the second carbon fiber layer is a sheet-shaped carbon fiber layer.

19. The method for manufacturing a cylindrical body according to claim 18, characterized in that a degree of impregnation of the first carbon fiber layer with the first thermoplastic resin and a degree of impregnation of the second carbon fiber layer with the second thermoplastic resin have a resin density of 40% to 70%.

20. A step of producing a cylindrical body by the production method according to claim 18 or 19; and mounting an optical element on the cylindrical body. A manufacturing method for manufacturing an optical device configured to be detachably attached to an imaging device.

Images